A 16-year-old Chinese girl has become a prisoner in her own bedroom after growing a full beard and moustache following life-saving drug treatment.

The teenager, known only as Nana, was diagnosed with aplastic anaemia - a malfunction in her bone marrow which stopped new cells sufficiently replenishing red blood cells - in 2010.

She spent time in hospital where she underwent a bone marrow transplant and ongoing drug treatment, but a side-effect of the medication was hirsutism – excess hair growth.

The Huffington Post reports that Nana's mum told China's Xinhua news agency that Nana would have died if she had not had the medication, but the ensuing hair growth meant that she was now too embarrassed to leave her room, or even to go to school.

"Everyday she cries, wanting to go to school," her mum said, revealing that her once 'lively' daughter was now virtually a recluse who wore a paper mask over her face if she had to go out in public.

The Xinhua news agency writes that Nana now spends most of her time 'hidden in her room reading books by herself'

"Doctors told us that the medication has strong side effects, but we can't stop it for her," her mum told reporters, "Since she was sick, she never looked at herself the mirror again".

"Hopefully once she is recovered and stops the medication, the hair could go away," she added.